I suspect that if the above stuff did not work, then there is no way outside of the editor to save a umap outside of the editor. Im guessing due to the fact that when a game gets packaged, the files get cooked, which strips out a lot of metadata. Which cannot be done during runtime. You may want to look at saving out ur maps to a custom format. And when the world gets loaded. Load in your custom format map and spawn in the necessary actors.